1. Technical Field
The present disclosure relates to systems and methods for testing or demonstrating functionality of vehicle diagnostics.
2. Background Art
Modern vehicles typically include controllers with on-board diagnostic (OBD) software to monitor performance of various vehicle and engine components and to alert the vehicle operator and/or service personnel when a particular component or system has degraded performance. Various prior art strategies for testing or demonstrating functionality of OBD software require special-purpose tools or computers connected to the vehicle controller to simulate various faults by applying a specified voltage or signal, grounding, or short-circuiting controller inputs and/or outputs to simulate a degraded component or system, such as disclosed in U.S. Pat. Nos. 5,798,647 and 6,014,504, for example. Similarly, laboratory testing, bench testing, dynamometer testing, etc. using special-purpose software and/or hardware devices to simulate vehicle operation and various component degradations has been used to validate vehicle diagnostics.
More recently, emphasis has been placed on in-use testing/demonstration of OBD monitor functionality. This in-use, or production vehicle, testing may be performed by replacing a functioning component with a degraded component to demonstrate that the appropriate OBD monitor activates a corresponding diagnostic code in the vehicle controller and/or alerts the operator with a service light or message depending on the particular code. However, there are several major disadvantages to using actual degraded components, including the cost associated with manufacturing special components with various types or ranges of degradations in performance for each different vehicle, and the resources required to replace functioning components with degraded components. For example, demonstration of some OBD monitors may require disassembling an engine to replace a functioning component with a degraded or failed component, which limits the number of times a component replacement can be made to demonstrate a threshold fault. In addition, generating repeatable and functional failures that demonstrate a specific OBD code can be difficult. For example, trying to retard operation of a mechanical component by a specified amount may be possible, but to get the same slow response over the entire production population or even the same vehicle over time may be very difficult to accomplish.